A wireless device may communicate with a first wireless network, such as a wireless local area network (“WLAN”) that uses one of the various Institute of Electrical and Electronics Engineers (“IEEE”) 802.11 protocols. The wireless device may communicate with other devices on the first wireless network. The first wireless network may additionally provide connectivity to one or more other networks, such as packet data networks, thereby allowing the wireless device to also communicate with devices on those other networks.
In addition to the first wireless network, the wireless device may also communicate with a second wireless network, such as a wireless wide area network (“WWAN”). The wireless device may connect to the second wireless network and then communicate with other devices on the second wireless network. The second wireless network may additionally provide connectivity to other networks, such as packet data networks. The wireless device may then also communicate with devices on those other networks.
The wireless device may communicate with one or both of the wireless networks, which can provide the wireless device with voice, data or other services. Although both wireless networks may provide the wireless device with one or more of these services, one wireless network may provide the wireless device with higher data speeds or lower access charges that make communicating with that network preferable. Therefore, even when the wireless device is communicating with one of the wireless networks, it might still be preferable for the wireless device to determine the availability of the other wireless network and then switch to communicating with that wireless network.
Further, the first and second wireless networks may have different coverage areas, thereby potentially creating areas where the wireless device might only be able to access one of the wireless networks. For example, as the wireless device changes location, it may leave the coverage area of one of the wireless networks and then only be in the coverage area of the other wireless network. If the wireless device were not already communicating with the other wireless network, it might be advantageous for the wireless device to detect that wireless network's availability and to begin communicating with that wireless network.
Current methods for detecting the availability of a wireless network have various limitations. In one method of detecting the availability of a wireless network, a user of the wireless device manually prompts the wireless device to check the availability of the wireless network, such as in response to a command from the user. This can disadvantageously create a delay in detecting the availability of the wireless network, because while the wireless device may be within range of the wireless network, the wireless device would only detect the wireless network if it receives the command from the user. A delay in making the request would cause a delay in detecting the wireless network's availability, and if the user did not even make a request, then the wireless device would not ever detect the wireless network's availability and may lose existing wireless network connectivity.
In another method of detecting the availability of the wireless network, the wireless device might automatically check for the wireless network's availability at predetermined time intervals. The wireless device might communicate with the wireless network using a radio or other transceiver, which the wireless device can power-up and then use to check the wireless network's availability. If the wireless network is not available, then the wireless device might power-down the radio until the next predetermined interval when it again check the wireless network's availability. Powering-up and powering-down the radio in this manner consumes battery power, which can be undesirable for battery-powered wireless devices. Similarly, continually leaving the radio on rather than periodically turning it on and off also consumes battery power and therefore may be undesirable.
Therefore, there exists a need for other methods for triggering a wireless device to perform predetermined actions, such as checking the availability of a wireless network.